Optical recording medium and optical recording medium recording device

Abstract

An optical recording medium such as DVD has a data recording area (103) in which data can be rewritten and a write-once area (104) in which data can be written only once and not be erased. A medium specific ID (105) which is specific to an optical recording medium is recorded in the write-once area (104). In the data recording area (103), a reflectance ratio of a part where the data is recorded is different from a reflectance ratio in a part where the data is not recorded. A reflectance ratio of a recording pit formed in the write-once area (104) is higher than the higher one of the reflectance ratios in the part where the data is recorded and in the part where the data is not recorded in the data recording area (103). Data recoding in the write-once area (104) is performed by irradiating to the write-once area (104) a laser beam with heat amount of three to 25 times heat amount necessary for recording rewritable data in the data recording area (103).

Description

TECHNICAL FIELD [0001] The present invention relates to an optical recording medium such as an optical disk for optically recording information and an apparatus for recording and reproducing the information to and from the recording medium. BACKGROUND ART [0002] In recent years, an optical disk is very actively applied to an AV (audio visual) appliance and a PC (personal computer). For example, a CD (Compact Disc) developed for music develops into a read-only CD-ROM for providing a program for the PC and an application, and further a CD-R capable of writing data once and a CD-RW capable of rewriting data are developed. These formats become a basic optical disk format that has been widely distributed in fields in AV or fields in PC. In addition, depending on development of a high density technology in recent years, a read-only type DVD (Digital Versatile Disc) format capable of storing an video data such as a movie has been rapidly distributed. In DVD, several types of format have be...

AI Technical Summary

Benefits of technology

[0032] According to Reference 1, the reflection film is also removed by the laser trimming to record the bar code type mark, so that falsification is difficult. However, a reproduction waveform thereof is made into a signal of which reflection light amount is reduced at a part of the bar code type mark as shown in FIG. 26. This reproduction signal resembles that according to the recording method disclosed in Reference 3 very well. If the BCA area 2502 is configured by a concavo-convex pit and the bar code type mark is formed by using the crystallization part and the non-crystallization part in the recording method disclosed in Reference 3, it is possible to acquire the substantially same signal.

[0035] The present invention is made taking the foregoing problems into consideration and an object of which is to provide an optical recording medium capable of effectively protecting the information from rewriting and falsification, for example, an optical recording medium suitable for copyright protection, and an apparatus for recording and reproducing the information in and from such an optical recording medium.

[0037] According to the recording medium having such a configuration, it is possible to record the recording pit of which reflectance ratio is increased in a write-once area. Therefore, the reflection light amount of the recording pit recorded in the data recording area is more decreased as compared to the state that the recording pit is not recorded, and on the contrary, the reflection light amount of the recording pit recorded in the write-once area is increased as compared to the state that the recording pit is not recorded, so that they can be distinguished and it is possible to easily detect the falsification of the medium specific ID information. Therefore, it is possible to easily detect the illegal disk having the medium specific ID recorded in a crystal of the phase change type and in a non-crystal thereof. Therefore, by using the optical disk having the data recorded therein in a method according to the present invention and the optical disk recording and reproducing apparatus according to the present invention, it is possible to realize a system having a very high security with respect to recording of the accounting information of the copyright protection and the content distribution or the like.

[0040] According to the present invention, since it is possible to discriminate data recorded in the write-once area from data recorded in the rewritable data area, if the medium specific ID is recorded in the write-once area, the data can be protected from the illegal copy and it is possible to provide a recording medium capable of being rewritten. In addition, encryption of the medium specific ID with information about the position where the medium specific ID is recorded allows the system to be protected from falsification of the medium specific information due to the illegal change of the optical disk apparatus. In addition, the write-once area can be used not only as the media specific information but also as information about accounting and management of the content. In this case, encryption of data to be recorded in the write-once area with the medium specific ID allows data recorded in the write-once area to be protected from falsification.

Problems solved by technology

The above-described recording method with a medium specific ID has a problem such that the medium specific ID is falsified.

Thereby, the medium specific ID that should be a specific number for each recording media can be changed and this lead to infestation of the illegal copy.

According to Reference 1, the reflection film is also removed by the laser trimming to record the bar code type mark, so that falsification is difficult.

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